title: PEGylated liposomal Gemcitabine: insights into a potential breast cancer therapeutic.
abstract: OBJECTIVE
  Nanoencapsulation of chemotherapeutics is an established method to target breast tumors and has been shown to enhance the efficacy of therapy in various animal models. During the past two decades, the nucleoside analog Gemcitabine has been under investigation to treat both recalcitrant and localized breast cancer, often in combination with other chemotherapeutics. In this study, we investigated the chemotherapeutic efficacy of a novel Gemcitabine-encapsulated liposome previously formulated by our group, GemPo, on both sensitive (4T1) and recalcitrant (MDA-MB-231) breast cancer cell lines.
  
  
  METHODS
  Gemcitabine free drug and liposomal Gemcitabine were compared both in vitro and in vivo using breast cancer models.
  
  
  RESULTS
  We demonstrated that GemPo differently hindered the growth, survival and migration of breast cancer cells, according to their drug sensitivities. Specifically, whereas GemPo was a more potent cytotoxic and apoptotic agent in sensitive breast cancer cells, it more potently inhibited cell migration in the resistant cell line. However, GemPo still acted as a more potent inhibitor of migration, in comparison with free Gemcitabine, irrespective of cell sensitivity. Administration of GemPo in a 4T1-bearing mouse model inhibited tumor growth while increasing mice survival, as compared with free Gemcitabine and a vehicle control. Interestingly, the inclusion of a mitotic inhibitor, Paclitaxel, synergized only with free Gemcitabine in this model, yet was as effective as GemPo alone. However, inclusion of Paclitaxel with GemPo significantly improved mouse survival.
  
  
  CONCLUSIONS
  Our study is the first to demonstrate the pleiotropic effects of Gemcitabine and Gemcitabine-loaded nanoparticles in breast cancer, and opens the door for a novel treatment for breast cancer patients.
authors.affiliation: BWH-HST Center for Biomedical Engineering, Harvard Medical School, 65 Landsdowne Street, Cambridge, MA, 02139, USA.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Papa
authors.forename: Almas
authors.initials: A
authors.lastname: Sidiqui
authors.forename: Sri Uma Aisvarya
authors.initials: SU
authors.lastname: Balasubramanian
authors.forename: Sasmit
authors.initials: S
authors.lastname: Sarangi
authors.forename: Matthew
authors.initials: M
authors.lastname: Luchette
authors.forename: Shiladitya
authors.initials: S
authors.lastname: Sengupta
authors.forename: Rania
authors.initials: R
authors.lastname: Harfouche
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000494:pharmacology; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D017239:Paclitaxel / Q000008:administration & dosage / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects; D000093542:Gemcitabine
chemical_list: D000964:Antimetabolites, Antineoplastic; D008081:Liposomes; D003841:Deoxycytidine; D011092:Polyethylene Glycols; D017239:Paclitaxel; D000093542:Gemcitabine